Nanoemulsions are well-liked drug delivery system in the pharmaceutical world. These are clear, thermodynamically stable and isotropic liquid-in-liquid dispersion with an average size range of 20 to 200 nm. They are having elevated surface area, strong stability, optically clear appearance, acceptable rheology and good drug loading capacity because of their characteristic droplet size. The methods used for the preparation of nanoemulsions include bubble bursting method, micro-fluidization, phase inversion temperature, emulsion inversion point, ultrasonication and spontaneous emulsification high-pressure homogenization etc. In the present paper, the advantages, methods of preparation and applications of nanoemulsions are critically reviewed.